Table 3. Univariate and multivariate analysis of factors associated with rheumatoid arthritis.
| Univariate | Multivariable | |||
|---|---|---|---|---|
| OR (95% CI) | P | OR (95% CI) | P | |
| Age, years | 1.09 (1.07, 1.1) | <0.001 | 1.09 (1.07, 1.11) | <0.001 |
| Male | 0.63 (0.46, 0.86) | 0.004 | 0.71 (0.48, 1.04) | 0.082 |
| Education (Ref: <9th grade) | 0.196 | |||
| 9th–12th grade | 0.71 (0.42, 1.19) | |||
| ≥13th grade | 0.58 (0.32, 1.03) | 0.0623 | ||
| Race (Ref: non-Hispanic white) | ||||
| Mexican American or other Hispanic | 0.61 (0.39, 0.97) | 0.038 | 0.54 (0.31, 0.96) | 0.036 |
| Others | 0.53 (0.32, 0.88) | 0.014 | 0.64 (0.37, 1.11) | 0.113 |
| Non-Hispanic black | 1.3 (0.88, 1.92) | 0.187 | 0.88 (0.56, 1.4) | 0.595 |
| Marital status (Ref: never married) | ||||
| Married/living with partner | 1.64 (1.13, 2.39) | 0.010 | 1.27 (0.77, 2.08) | 0.344 |
| Widowed/divorced/separated | 3.62 (2.48, 5.28) | <0.001 | 1.41 (0.76, 2.61) | 0.270 |
| Poverty | 2.14 (1.41, 3.25) | <0.001 | 2.96 (1.88, 4.65) | <0.001 |
| Covered by health insurance | 1.48 (1.01, 2.16) | 0.044 | 1.81 (1.12, 2.93) | 0.016 |
| Regular smoking | 2.18 (1.62, 2.95) | <0.001 | 2.19 (1.49, 3.21) | <0.001 |
| Level of drinking (Ref: non-drinker) | ||||
| Moderate | 1.44 (0.86, 2.41) | 0.169 | ||
| Heavy | 0.88 (0.48, 1.64) | 0.698 | ||
| Occasional | 1.34 (0.59, 3.07) | 0.484 | ||
| Obesity (Ref: normal or underweight) | ||||
| Overweight | 1.21 (0.85, 1.74) | 0.293 | 1.29 (0.85, 1.94) | 0.232 |
| Obese | 3.26 (2.21, 4.82) | <0.001 | 3.31 (2.05, 5.36) | <0.001 |
| Appropriate sleep duration | 0.37 (0.27, 0.49) | <0.001 | 0.46 (0.32, 0.65) | <0.001 |
| HIV positive | 1.34 (0.28, 6.42) | 0.718 | ||
| Osteoporosis | 7.13 (3.44, 14.77) | <0.001 | 3.68 (1.64, 8.22) | 0.002 |
| Diabetes | 5.59 (4.09, 7.64) | <0.001 | 2.00 (1.35, 2.95) | 0.001 |
| Caffeine intake (Ref: none) | ||||
| Recommended | 1.12 (0.72, 1.74) | 0.616 | ||
| High | 1.32 (0.82, 2.12) | 0.250 | ||
| Milk consumption (Ref: regular consumption) | ||||
| Never | 0.83 (0.57, 1.2) | 0.322 | ||
| Irregular | 0.88 (0.62, 1.25) | 0.486 | ||
| Excess total saturated fatty acid intake | 0.95 (0.34, 2.62) | 0.916 | ||
| Vitamin A intake (Ref: recommended) | ||||
| Insufficient | 0.92 (0.66, 1.28) | 0.628 | 0.70 (0.50, 0.98) | 0.036 |
| Excess (toxic) | 4.22 (1.01, 17.61) | 0.048 | 1.74 (0.17, 17.37) | 0.636 |
| Inadequate vitamin B1 intake | 1.28 (0.94, 1.75) | 0.112 | ||
| Inadequate vitamin B2 intake | 1.1 (0.84, 1.43) | 0.494 | ||
| Inadequate vitamin B6 intake | 1.23 (0.94, 1.6) | 0.132 | ||
| Inadequate vitamin B12 intake | 0.81 (0.57, 1.15) | 0.234 | ||
| Inadequate vitamin C intake | 0.87 (0.61, 1.24) | 0.455 | ||
| Inadequate vitamin D intake | 1.03 (0.51, 2.08) | 0.927 | ||
| Inadequate vitamin E intake | 0.55 (0.11, 2.66) | 0.454 | ||
| Inadequate vitamin K intake | 0.93 (0.66, 1.31) | 0.682 | ||
| Niacin intake (Ref: recommended) | ||||
| Insufficient | 0.99 (0.62, 1.6) | 0.982 | ||
| Excess | 0.84 (0.61, 1.15) | 0.272 | ||
| Folate intake (Ref = recommended) | ||||
| Insufficient | 1.16 (0.9, 1.48) | 0.254 | ||
| Excess | 0.65 (0.39, 1.1) | 0.109 | ||
| Inadequate calcium intake | 1.11 (0.84, 1.47) | 0.455 | ||
| Inadequate iron intake | 0.92 (0.7, 1.2) | 0.518 | ||
| Inadequate magnesium intake | 1.06 (0.81, 1.39) | 0.671 | ||
| Inadequate phosphorous intake | 1.37 (0.94, 2.01) | 0.103 | ||
| Inadequate potassium intake | 0.87 (0.53, 1.42) | 0.582 | ||
| Excess sodium intake | 0.66 (0.45, 0.96) | 0.031 | 0.80 (0.47, 1.30) | 0.348 |
| Inadequate zinc intake | 1.06 (0.76, 1.49) | 0.728 | ||
| Inadequate copper intake | 1.42 (1.06, 1.89) | 0.019 | 1.31 (0.89, 1.95) | 0.175 |
| Inadequate selenium intake | 1.55 (0.98, 2.45) | 0.060 | ||
Notes.
- OR
- odds ratio
- CI
- confidence interval
- Ref
- reference group